1. Field of the Invention
This invention relates to slide fasteners, and in particular to improvements in a separable slide fastener of the type comprising a box-and-pin separable coupling and an automatically locking slider.
2. Description of the Prior Art
A slide fastener has been known and used extensively which incorporates an automatically locking slider with a pair of fastener stringers having a box-and-pin separable coupling designed to permit ready connection and disconnection of the stringers. In such a separable slide fastener, the slider rides on the box-side row of fastener elements or scoops when the fastener is separated, and the fastener stringers can be connected together as the pin member of the separable coupling is inserted into the box member through the slider held in abutting contact therewith. It has also been known to spring-bias the locking member or pawl of the slider into a position of interference engagement with only the box- or the pin-side row of fastener elements. The slider of either type has its own advantages and disadvantages.
An automatically locking slider with its locking member spring-biased into a position of interference with the pin-side row of fastener elements, for example, is free to move in either direction along the box-side row of fastener elements when the fastener is separated. A difficulty arises, however, in connecting the pair of fastener stringers, since the locking member hampers the insertion of the pin member into the box member through the slider.
The above disadvantage is totally absent from a slider having its locking member urged into interference engagement with the box-side row of fastener elements. A difficulty is also encountered with this type of slider, however, in the case where the slider is locked in a position away from the box member when the fastener is separated. The slider is then not smoothly movable into contact with the box member unless its pull tab is properly manipulated to unlock the slider and hold same unlocked during its movement into contact with the box member.